This invention relates to a processing solution of a light-sensitive silver halide color photographic material and a processing method of the same, more particularly to a processing solution of a light-sensitive silver halide color photographic material which is improved in processing stability and color staining, and also little in fluctuation in maximum density of cyan dye or magenta dye and a processing method of the same.
Processing of a light-sensitive silver halide color photographic material basically comprises the two steps of color developing and desilverization, and desilverization comprises the bleaching and fixing steps or bleach-fixing step. Other than these steps, rinsing processing, stabilizing processing, etc. may be added as the additional processing steps.
In color developing, exposed silver halide is reduced to silver simultaneously with the reaction of the oxidized aromatic primary amine type developing agent with a coupler to form a dye. During this process, halogen ions formed by reduction of silver halide are dissolved and accumulated into the developing solution. Also, separately, components such as inhibitors, etc. contained in the light-sensitive silver halide photographic material are also dissolved out to be accumulated into the color developing solution. In the desilverization step, the silver formed by developing is bleached with an oxidizing agent, and subsequently all the silver salts are removed with the fixing agent as soluble silver salts from within the photographic light-sensitive material. Also, one bath bleach-fixing processing method is known, in which the bleaching step and the fixing step are comprehensively processed at the same time.
In the color developing solution, color developing inhibitors are accumulated by developing processing of the light-sensitive silver halide color photographic material as mentioned above, while the color developing agent or benzyl alcohol, etc. are consumed or brought out as accumulated in the photographic light-sensitive material, whereby the concentrations of such components will be lowered. Accordingly, in the developing processing method in which a large amount of light-sensitive silver halide color photographic materials are continuously processed by means of an automatic developing machine, etc., a means for maintaining the components in the color developing solution within the range of constant concentrations, in order to avoid change in finished characteristics of developing dye to change in component concentrations. As such means, there is ordinarily used the method in which a supplemental solution for supplementing components in shortage and diluting the unnecessary increased components is supplemented. Due to supplement of the supplementing solution, a large amount of overflow will necessary occur and discharged, and therefore, this method poses a great problem in economy and pollution. Therefore, in recent years, for the purpose of reducing the above overflowed solution, there have been proposed the regeneration method of developing solution according to the ion exchange resin method or the electrodualysis method, the concentrated low supplement method, and further the method in which the overflowed solution is added with a regenerating agent to be used again as the supplementing solution. Among them, the concentrated low supplement method may be said to be the method which is extremely suitable for a small scale laboratory such as mini-laboratory, because no special new device is required and processing management is easy.
On the other hand, in a conventional color developing solution, for the purpose of preventing oxidation of an aromatic primary amine color developing agent as represented by p-phenylenediamine type developing agent, a sulfite, or sulfite and a water-soluble salt of hydroxylamine are added as the preservative.
Since storability is not necessarily sufficient if these sulfites are added singly into the developing solution, it has been already known that more effective preservability can be obtained by adding hydroxylamine as a water-soluble salt.
However, it has been known that a hydroxylamine salt is not only decomposed by receiving the catalytic action of co-existing minute amount of metal ions, particularly iron ions to be reduced in the preserving effect, but also ammonia is generated by decomposition, whereby fog or contamination is formed on the light-sensitive color photographic material, or abnormality in photographic characteristics, particularly hardening in tone at the shoulder portion may be caused to lower processing stability.
Such mixing of metal ions, particularly iron ions into a color developing solution occurs by the so-called back contamination in which a bleaching solution or bleach-fixing solution employing conventionally ferric salts of an organic salt as the bleaching agent is carried over into the color developing solution by splashing or by means of a conveying leader, or a hanger for hanging a belt or a film.
For preventing these undesirable actions of metal ions, the technique of incorporating various metal chelating agents has been proposed and practically applied. For example, there may be included the technique in which hydroxyalkylidenediphosphonic acid sequestering agent and lithium salt are used in combination as disclosed in U.S. Pat. No. 3,839,045, the technique in which a polyhydroxy compound and an aminopolycarboxylic acid sequestering agent are used in combination as disclosed in U.S. Pat. No. 3,746,544, and the technique in which a polyhydroxy compound and an aminopolyphosphonic acid sequestering agent are used in combination, etc. However, even by used of these techniques, the problems as mentioned above cannot be solved under the present state.
Such lowering in processing stability caused by hydroxylamine salt is more amplified in the low supplement processing. That is, in the low supplement processing, not only the metal ions accumulated are increased, but also renewal rate of the developing solution is lowered, whereby the residence time in the processing tank of the developing solution is remarkably increased. For this reason, the problems of generation of fog, hardening in tone at the shoulder portion by decomposition of the hydroxylamine become further marked. Also, under such situation, it has become clear that decomposition acceleration of hydroxylamine salt occurs by minute metals contained in reagents, which have little effect in the much supplement processing of the prior art, particularly copper ions. Against the copper ions, it has been found that use of a chelating agent of the prior art proved to be difficult in intoxication thereof.
Accordingly, the present inventors have investigated variously above preservatives free from the drawbacks of lowering in processing stability possessed by hydroxylamine salt, and also high in preserving ability, to accomplish the present invention.
Further, as the result of investigation of the use technique of the specific preservative to be used in the present invention, it has been found that the maximum density of cyan dye or magenta dye is susceptible to influence by the change in concentration of the specific preservative to be used in the present invention. That is, if the concentration of the specific preservative to be used in the present invention is elevated, the maximum density of cyan dye or magenta dye is liable to be lowered. The reason for having influence on the maximum density of cyan dye or magenta dye is not necessarily clear, and cannot be explained by simple coupling inhibition or inhibition of silver development, but it may be considered to be due to the balance between silver development and coupling which tends to be readily unbalanced.